In electronic engineering technologies, a DC-to-DC converter is a common power conversion module that converts a DC voltage to another DC voltage. Recently, as the electronic device is developed toward miniaturization, a three-dimensional layout configuration of the DC-to-DC converter is gradually adopted in order to effectively reduce the area of the circuit carrier board.
FIGS. 1A and 1B are schematic exploded and side views illustrating a conventional DC-to-DC converter, respectively. In the DC-to-DC converter, a printed circuit board is used as a circuit carrier board 10. Many electronic components (e.g. a semiconductor IC chip 11 and several passive components 12) are mounted on the circuit carrier board 10. In addition, four post-like or ball-like structures 101 are formed on the corners of the circuit carrier board 10. An inductor 13 is soldered on the four post-like or ball-like structures 101. After the inductor 13 is soldered and supported on the four post-like or ball-like structures 101, a receptacle 19 is defined between the inductor 13 and the circuit carrier board 10. The semiconductor IC chip 11 and the passive components 12 are accommodated within the receptacle 19. As such, the three-dimensional layout configuration of the DC-to-DC converter is achieved.
Although the three-dimensional layout configuration may reduce the area of the circuit carrier board, there are still some drawbacks. For example, since an additional process is required to form the four post-like or ball-like structures 101 on the circuit carrier board 10, the material cost and the fabricating cost will be increased. Moreover, due to the inductor 13, the electronic components on the circuit carrier board 10 are usually suffered from an electromagnetic interference (EMI) problem. Under this circumstance, the performance and operating efficiency of the DC-to-DC converter are usually unsatisfied.